How to export particle cache rotate channel for Type - Granular with DY_Domain? (for later use with instanced objects)I tried to activate rotate under Export: Particles cache rotate channel under Check options and in Export CentralI then get this error message.

"WARNING: The particle channel "rotation" for node DY_Domain01 has not been computed. Go to the "Particle Channels" panel and activate the option to compute this channel."

Is this a bug?

Because under Particle Channels in the DY_Domain - Domain menu there are only options to activate Vorticity and Normal.

This really sounds like a bug. Or better: it seems as if the developers forgot to enable "rotation" by default or add a checkbox to calculate this channel on demand. I'll tell the RF developers about this issue.

I've forwarded this issue to our developers and they explained me the meaning of the rotation and conform_tensor channels:

Rotation is only required with "Viscous", and "Viscoelastic" requires rotation and conform_tensor, esp. when you want to resume simulation with these materials. In this case, the channels should be activated to guarantee a correct behaviour. What's definitely wrong is the warning you got, because it's completely misleading: with granular or liquids the two channels are not necessary and have zero meaning.

Sorry for the wrong information in my first post, but the explanation of rotation and conform_tensor was new to me as well. So, the only "bug" is the warning.